A magnetic disk drive which functions as a disk device comprises a housing which includes a base and a top cover, and the housing accommodates a rotatable magnetic disk and a rotatable head actuator which supports a magnetic head. The housing further accommodates a stopper which stops the head actuator, which is a movable member, at a predetermined rotation position, or a stopper which regulates a range of movement of another movable member.
To reduce the collision impact of the head actuator or the other movable member on the stopper, the stopper comprises a cushioning member (stopper rubber) which is made of a rubbery elastic material or the like. As the material of the cushioning member, in light of impact attachment characteristics, fluorine rubber is often used. However, fluorine rubber is highly adhesive, and if the head actuator is left in contact with the cushioning member for a long time, the head actuator will be fixed to the cushioning member. In that case, the head actuator will not move next time when the disk device is activated.
To prevent such fixation, a method of providing a plurality of projections on the outer surface of the cushioning member and reducing the contact surface of the cushioning member with respect to the head actuator, a method of providing a fixation prevention film on the surface of the cushioning member, and the like have been proposed.